Slicing Up Some Pi

Building a circle cutter jig for use with the plasma torch has been on my list of things to accomplish in my lifetime. Since I am not sure how much time I have left I figured I had better spend an evening completing the task before it is too late. I really do not know what is available to purchase when it comes to circle cutters. I admit I have spent no time looking around to see what the standard design is. I have seen some jigs for an O/A set up that has a nice rolling wheel and the works. I decided to go purely from scratch and approach it with no firm plan.

 I started digging through the metal piles looking for something that could be morphed into a useful tool. The plasma torch is a standard 1 inch OD which makes things easy. I had some left over pipe from the metal bender that would do the trick to use as the torch head holder. The rest of the parts were some scrap steel rod, a 3/8 inch coupler nut and some 3/8’ threaded rod.

The build is really not worth writing about. The design was simple. Take a look at the pictures and you can pretty much figure out how the build went. The main reason for using threaded rod is purely for adjustment and flexibility. I can adjust for just about any radius circle I need. If the rod gets too long I can always machine some mid-way support wheels to help with the stability.

Pin should have been mounted on the inside of the circle – oops

 

 At a later date I might machine a centering adapter for the torch head holder. This way I can drop the adapter into the end were the torch head would normally be inserted and then I will set my radius precisely using the adapter first. Basically it would allow me to measure my radius using two pencil tip points instead of having to measure to the torch tip.

 

 The operating instructions are simple. Determine the radius of circle you want to cut and set the distance between the centers. Take the metal that needs to be cut and determine where the center of the circle is and give it a good center punch. Next step is just go to town and plasma out the circle.

 I shot a quick video of the very first cut using the tool. As you will see I still need to develop some coordination in order to use it a bit better. However for the first cut it worked out fantastic. I used a 12” wide section of 10 gauge steel to cut an 11.875” circle. The steel was too narrow to support the height guide on the torch end of the tool but everything still worked out fine. As I am writing about this flaw I just realized I screwed up. I don’t know why I mounted that pin on the outside of the torch holder, I should have drilled the holder and welded the pin on the inside circle. Oh well…I can fix it yet.

hAckermann Geometry

 

So as I have some “in between” evening time I continue with the gravity racer build. I am having a lot of fun building the car and I think it is because I don’t feel as though I needed to come up with a game plan or need to stick to one. I am totally building on the fly and using whatever resources I have in the shop.

I need to get it to rolling chassis stage. I decided to hack my way through the steering set up. I wanted to run a conventional automotive style steering which includes a couple of steering knuckles. I know some gravity racers run a solid axle supported by a center pivot however for this car I want to give it some responsive steering. I plasma cut out a couple of rough looking knuckles from a chunk of 2.5 x 1.5 rectangular tubing. I cut them out in such a way that they would each have a steering arm attached. I wasn’t sure how strong they would be so I beefed them up with some .250” plates. The 5/8 “ axle bolts got welded in, I then gave the units a quick blasting in the sandblast cabinet and the spindles were set.

Now what to use for a front axle. I had some chunks of old ¾” gas pipe lying around. My instincts told me to machine up some king pin bushings so that I could bearing mount the spindles however I am trying very hard to stay focused on time. I have no time for this build so…the front axle comprises of the gas pipe with a couple of holes drilled perpendicular in each end. Yes the holes are going to see some wear however this car is not going to get steered an excessive amount, wear will be minimal. I chose to run .500” bolts as king pins and intentional stacked up washer to take up the play. The idea behind using multiple washers is that I will be able to apply lube in between all the washers to help turn them into a poor mans bearing.

So with the knuckles fabricated and the axle dealt with I needed to get the assembly mounted to the frame. I using a couple of 1.5” muffler clamps and welded some angle iron brackets to the frame. Not only are the muffler clamps cheap and easy but they would also allow me to build some caster into the front end to help with the straight line stability. I haven’t actually measured the caster but I suspect I dialled it in around 10 degrees.

 So now I need to come up with some way to steer the wheels. But before I could calculate steering wheel placement I needed to fab a seat in order to test fit the driver’s position. I needed something cheap, light, strong, and comfortable for a seat. I had access to a whole bunch of seat belts so I cut the belts off and proceeded to weave a seat out of them. I ended up using a large head 3/16” aluminum rivet to hold each weave together. With the basic seat constructed I was able to set it into rough position in the car and get a bead on steering wheel position.

 The steering wheel is going to be race car bow tie style. I bent some 3/8” CR round bar in the Hossfeld clone bender. With a support plate plasma cut out I welded on the steering wheel handles. The steering column is made from ½” CR round bar. With a 5/8” coupler nut welded on I was able to bolt my bow tie wheel on. Once the car is aligned I will weld the bolt, steering wheel, and column together to ensure nothing come loose. The upper column got supported using a purchased flange bearing. The lower column is supported by a fabricated steel plate welded to the front axle housing.

 It was onto the tie rods and the “rack and pinion”.  The outer tie rods are purchased 5/16” ball rod ends while the inner tie rod ends are adjustable yokes. I wanted to build some slop in the inner rod ends to ensure no binding of the steering. The inner and outer tie rod ends are joined by a 5/16” NF threaded rod to allow for front toe adjustment as well as compensate for rear tracking. The “rack” was pure guess work. I was unsure what ratio to build it. I decided to go close to a 1:1 steering ratio. The rack comprises of nothing more then a triangle cut chunk of .125” steel with 3 holes drilled in it. The top hole was drilled to allow for the column shaft to slide through. Once the column position was determined the rack got welded onto the steering shaft.

 So their you have it. Quick and dirty but yet 100% functional. The steering ratio feels good. The front caster makes for tough dry steering but I suspect the stability will be great. Next I will move onto the rear axle and the brakes. We’ll see what the garage scraps will allow me to come up with.

Squaring The Shorts Will Give You The Long Of It

I wanted to take a different angle with celebrations this month so I figured I would do a complete 180. In continuing with recognizing individuals who have made a significant contribution to garage projects I thought it was time to acknowledge those who have helped out with the design aspects. Any project, no matter how small or large, takes some sort of planning or engineering. Nothing turns into something without first a plan. As projects get more complicated the planning required typically involves a lot more mathematical calculations. There have been all sorts of computer programs developed to assist with the math, programs such as AutoCAD. Well there is one mathematical formula that I use more then any other calculation when designing projects. This formula is so versatile that you can perform the basic calculations in your head and at the very most you would need a calculator capable of the square root function. The formula I speak of is the Pythagorean Theorem. And who gets credit for this one? Well it would be Pythagoras of Samos who lived from 570 to 495 BC. Now there is some debate as to who should actually be credited with the discovery of this formula. Some say that it was actually the Babylonians that first discovered the details and others say that it may not in fact been Pythagoras of Samos but instead his students that came up with the theory. In any case I am going to give Pythagoras the credit. If at a later date someone proves this wrong then I will be sure to update this post. Anyway…the point is this; the guy is credited for coming up with the formula to calculate the hypotenuse of a right angle triangle. The simple formula is a2 + b2 = c2. Carpenters know it as the 3 – 4 – 5  rule when calculating a right angle. I am not going get into explaining the formula and the theory behind it, plenty of others already have. The point is this; Pythagoras rocked the show when he let this calculation out of the bag. The number of opportunities that I have been given to use this equation is countless. As far as I am concerned this should be grouped in with basic arithmetic. So if you are building with straight lines and you want to come up with something more then just a box then may I suggest you add up your A squares and B squares and pound that square root key. Pyth you get 2 thumbs up today for lending a hand to planning projects.

The Perimeter is Secured

 

So my railings sat at the powder coaters for a week and a half but they finally were completed. The coating had turned out fantastic. The color that had finally been decided on was a textured flat black. I had previously ground some of the visible welds and so with the powder coating added to the smoothed out seams the finish looked great. Like I have talked about previously I have always struggled with finishing procedures. Normally the railings would have got a coat of Tremclad tossed on them however I have zero regrets going with powder coating. It gives the project a very pro look to it.

 At last I would be able to see some completion with the railing project. Like always the most satisfying parts of the projects are always so short lived. It is always the behind the scenes work that ends up being so time consuming. When the time comes to see everything come together the work doesn’t last long enough for my liking.

 To mount the railings into the gazebo was simple. All the sections had already been custom fabricated to their pre determined locations. The holes were already marked from when I mounted the railings in the jig. Nothing more then drilling some holes and screwing each section into place. They all got attached using 3 inch pan head screws. I would love to eventually find a supplier of black hardware. The odd fastener is easily found in a black finish but for the most part I end up having to finish the screws and nuts myself. I sandblast all the new hardware to get rid of the shiny chrome finish. Then they all get a few coats of flat black spray bomb. The hardware doesn’t take any abuse so the spray bomb is sufficient.

 The steel railings were going to get capped of with a wooden handrail. I wanted to add the wood to them simply to help tie everything together. The railing caps were pressure treated lumber purchased pre-fabbed in 6 foot lengths. They all got a couple coats of paint first before getting chopped up and installed. Since all my main support posts for the gazebo are not set 100% accurate in regards to their angle I needed to custom set every angle for every railing section before slicing them up with the chop saw. It was well worth the added effort. The railing caps were attached to the steel railings using a half wood screw and half machine screw stud. I had already predrilled the steel before sending them out to the powder coaters. It was a simple procedure of marking holes, drilling, and clamping the caps down using acorn nuts that, too, were sandblasted and painted.

 2 of the 3 flower box holders were hung and the flower boxes were dropped in place. Voila, finito compleato! Railings for the gazebo? Check! The railings are officially done. Many years ago I used to be one of those guys that always had 1 or 2 lingering details that still needed to be finished after completing a project. I have finally trained myself to reach for completion and when the project is done that means it is actually done. In the case of the railings, they are done!

 So what’s next? Well there are a few things on my plate. I need to get back onto the fireplace I started, next stage in that project will include some metal fabricating in the garage. I still have the soap box for my daughter that is somewhat of a side project but I do need to get it done soon so that some enjoyment can be had before the snow falls. Then there are always a few side projects I have on the go for other people.

 The soapbox is a priority “in between” job. Unfortunately I need to introduce a new project into the mix. The issue is this. I like nature and I like wildlife. I enjoyed working along side the robins that had previously shacked up in my gazebo. In fact it was just recently discovered that we have another birds nest in one of our spruce trees. What the species is I am unsure. However there has been lots of bird activity in the yard. I like that. I always try and give wildlife their space and I try and be respectful of there habits and need for survival. So here comes the issue…we have got rabbits scattered throughout the neighbourhood. It is getting to be a serious issue. They ended up destroying hundreds of trees this past winter by chewing the bark off clean. I called the cities fish and wildlife department to enquire as to any policies in place to deal with this growing problem. The city has no plan and they had no interest in discussing it any further. The problem is getting worse. I have caught numerous baby bunnies that seem to make my yard their home and then my daughter and I take them up to local woodland near by and let them run free there. Okay so what does all this have to do with my next project? My back yard is fenced and completely secure from rabbits except for a section that is waiting for a gate. The gate posts were set in place a few years back, I just haven’t built a gate yet. This weekend was the last straw, the rabbits chewed down the wife’s clematis again. So next up is a gate and therefore the fortress will then be secure. What’s the design? I don’t know yet but it will involve welding and it may involve some lumber to help tie the look in with the rest of the fence. I’ll figure it out as I go.

9.81m/s Under the Hood

 So I was approached the other day by someone who had a specific request and was looking to me for some help. Right away I thought to myself “I do not have time for this”, I have my summer lined up with projects that need to see completion before the snow flies. Out of courtesy I gave this individual a few minutes to state their case before I proceeded to tell them no. It turns out that their freedom was at stake. They had been feeling the pressures of life and they needed something new and exciting. They are confined close to home due to physical reasons and need to rely on others to take them places and help them accomplish certain tasks. At this point in life this individual is really incapable of providing for herself. As I listened to this person’s story I tried to maintain focus, my game plan was simply to listen and kindly, and respectfully, dismiss this person. As she continued to talk it turns out she was in need of a whip for herself, to help her go places and see the world. She thought it was time for her to step into car ownership. When I began to quiz her regarding just want is involved in obtaining and maintaining a vehicle I was met with a blank stare. Obviously this person is in way over her head and it became very clear that she would require a high level of help. I could feel myself getting sucked into her plea; I resisted and attempted to fight the sympathy I began to feel. I worked to maintain a cold heart and tried to emit an uninviting composure. It was no use; she was determined to get her way. I had enquired regarding the financial side of things; apparently this person has no resources or money to fund the project. When I asked what skills she possessed or where she thought she could make a contribution I was told that she can design and paint. Well at least I’m getting something out of her. After further discussions she was able to break me down. I started off strong and in the end I crumbled.

 So here is the new plan, my 5 year old daughter needs a “soapbox” car. I am going to try and squeeze it in between my other planned projects. My daughter came up with the concept drawing so between the 2 of us we will try and build something that resembles her vision. As far as specs go there is an issue. In the part of the world we live in there is no standardized soapbox derby racing. There are many towns in the surrounding area that hold their own derby’s however each town also makes all there own rules in regards to car design. If there was an existing standard already established then I would follow it but I have decided to spec the car the way I want and choose not to run it in derbies. In the area of town I live in we have lots of fresh paved hills in the area that have low, or no, traffic. The car will be built purely for enjoyment.

 The budget is low. The idea is to be inventive and use as many parts I can that I already have lying around. We are also going to build on the fly, obviously there is a rough game plan in place but how exactly everything is going to fit together is not yet known. With a couple lengths of 1 x 1 x .065” square tubing I had laying around they were cut to length and then run through the metal bender to get some radius. Using some leftover .5 x .5 square tubing from the railing project I was able to tack together a basic tub. I’m going for the classic derby looking cars with the tear drop shape.

 So the client and I headed out to pick up the supplies to create the rolling chassis. Wheel selection is a big one. Initially some pneumatic type wheels were considered however in the end we decided to outfit the car with a set of  10″ x 2.25” higher quality speed wheels. The front steering is going to feature a set of steering knuckles coupled to some adjustable tie rod ends. The steering column will involve connecting the steering wheel to the knuckles through a solid mechanical means; we’re not using cables or ropes. This thing has to be able to rail through the corners. The front axle will incorporate a way to build some positive caster in as well as front toe will be fully adjustable. We’re shooting for 0 degrees of camber. Because the chassis is not sprung we do not anticipate any flex in the front steering therefore 0 degrees of camber will give us maximum tire contact patch. We will decide on the front caster angle as time goes, I suspect anywhere between 8 – 14 degrees will give is some nice straight line stability.

 So as things sit now the tub is mocked up and the majority of the components have been collected. The basic shape has been built and we are onto axle fabrication. We will work to get it to rolling chassis stage and then we will be able to figure out cockpit size and placement. The build won’t be overly pretty and it will not scream precision engineering or built. As long as it is functional, safe, and gives my daughter and I an oppurtunity to have some fun I will consider to project a success. For now the gazebo railings are sitting at the powder coaters waiting for completion so this will be a good project to fill the gap.

 

Well Hung

 With the railings all welded up it was time to focus on the planter boxes. Here’s the scoop, the wife has 3 planter boxes that need to be hung on 3 of the railing sections. At first I was going to weld some decorative brackets onto 3 of the railings but then plans changed. First of all the boxes that have been chosen are plastic and not of the highest quality, in other words, I do not think they have a very high life expectancy. As I am writing this I am unsure why I didn’t plan on just fabricating the planter boxes myself from scratch. Oh well…the boxes have been purchased and the plants have been planted. Anyways back to the point. I don’t want to commit to a specific size planter box just in case the boxes change in the future and are a different dimension or maybe one year the plants don’t get planted. The second thing is that it was requested that the holders be as inconspicuous as possible, I said I would try. So the new plan is this; make the box holders removable. My plan does not include some kind of hook system where the holders just hang of the railings. The holders are going to get bolted on so they sit solid and hang straight. With the holders removable I can always weld up different ones should different size boxes ever need to be accommodated.

 To be able to bolt the holders on I wanted to come up with a system that was strong but also would not interrupt the lines of the railings. I chose to spin some steel spacers on the lathe. The spacers would get welded to the underside of the top railing horizontal member and allow bolts to pass through them in order to secure the holders. I hate the look of standard cap screw hardware. I was going to use socket head bolts for fasteners but instead switched to carriage bolts at the last minute. The 5/16” carriage bolt heads all got their head diameters cut down to .600” to match the diameters of the spacers. The “squares” that sit under the bolt heads also got trimmed off to allow the bolt heads to sit flush against the spacers.

 The main support brackets were built form left over 1.250” x .250” flat bar. Their lengths were all cut a bit long and then they all received a 90 degree bent. Getting the flat bar glowing red using an oxygen acetylene torch helped bend the .250” thickness like butter. The final lengths could now be determined and they were trimmed to size using the plasma that way I could give the edge a nice radius. I tool that I had purchased awhile back was a 1” x 30” belt/disc sander. It always takes time for me to start to incorporate the new equipment into the building routine. This guy had been sitting on the shelf for awhile however I have recently stated to use him. I think it may become my new favourite tool. The sander is great for cleaning up edges let over from cuts and always does a nice job of cleaning of radius cuts. With the brackets trimmed and bent the holes got marked and drilled.

 The rest of the hanger is going to get finished with some 3/8” cold rolled round bar. I have about 90% of the vision of what the finished job should look like. The other 10% will get done on the fly. Using the Hossfeld clone bender I was able to bend some visually pleasing angles into the bar to allow for a simple yet effective planter box holder.

 I think overall the holders worked out well. They look good, they are strong, they are removable, and they are simple. Other then having to lay down a few more welds and drill a few holes the railings are just about ready for the powder coaters. This is where the greatest stumbling block will need to be dealt with. At this point in time the wife and I are in the middle of a disagreement regarding color. She wants grey, I want a textured flat black. I think the gazebo already has too much grey on it and I think the black will give it some subtle contrast, plus it will match the fence. She thinks that because the roof is cedar, the gazebo is grey, and the furniture is brown that by making the railings black it would be introducing too many colors. 99% of the time I let her make the color call on everything because I know she is better at choosing them then I am but…I am really unsure about this one. Thoughts?